The present invention generally relates to needle assemblies. More particularly, the present invention pertains to a safety mechanism for use in connection with needle assemblies including hypodermic needles, catheter needles and other medical instruments.
Needle assemblies used in medical procedures have been and continue to be a concern from the standpoint of healthcare worker safety. For example, accidental needlesticks with a used needle present the possibility for transmission of disease. A basic form of needlestick prevention involves the use of a rigid cylindrical cap which is positioned over the cannula and engages the hub to which the cannula is connected. During use, the cylindrical cap is removed to expose the cannula. After using the syringe/needle assembly for its intended procedure, the cylindrical cap must be once again mounted on the hub to cover the used cannula. Oftentimes, the healthcare professional tries to reposition the cylindrical cap on the syringe/needle assembly by xe2x80x9cscoopingxe2x80x9d the cylindrical cap with the syringe/needle assembly. As can be appreciated, this may not be an easy or effective technique for repositioning the protective cap on the syringe/needle assembly. Also, the cap may become accidentally dislodged from the syringe/needle assembly, thus exposing the used cannula and presenting a potential danger.
Other proposals have also been made to protect healthcare professionals from needle stick hazards. These proposals are generally divided into three categories: 1) hinged recap devices in which a hinged sleeve is pivoted into a permanently locked position with respect to the cannula; 2) spring-loaded retractable cannula devices in which a spring-connected cannula is activated and the cannula in turn is retracted into the syringe barrel or the syringe plunger; and 3) sliding barrel devices in which the syringe barrel is formed by two concentric cylinders, the outer one of which is slid by the health care worker towards the cannula after use to cover the cannula. Although these assemblies provide some measure of protection against accidental needlesticks, difficulties remain.
For example, hinged recap devices are assembled between the syringe and needle assembly. This construction introduces dead space between the cannula and the syringe, thereby resulting in the waste of expensive medication. Retractable cannula devices run the risk of inadvertently retracting, thus wasting a syringe and once again presenting the possibility of wasting expensive medication. Additionally, the velocity of the cannula retraction could result in the spraying or splashing of fluids or medication, thus actually increasing the healthcare professional""s exposure risk. The sliding barrel design is disadvantageous in that it almost doubles the length of the syringe from the unused position to the used/disabled/engaged position, thus substantially increasing the volume of biohazard waste and possibly creating exposure hazards because the syringe/needle assembly does not adequately fit into the sharps container.
Other concerns associated with at least the hinged recap devices relate to packaging and usage. When using hinges recap devices, it may be desirable to rotationally fix the position of the hinged sleeve relative to the cannula so that the hinge sleeve does not rotate relative to the cannula and hub during use. However, the distal end of the cannula is typically provided with a bevel which at least some users prefer to orient in a particular direction during use. If the hinged sleeve is designed to be rotationally fixed, the hinged sleeve may interfere with the user""s view or manipulation of the cannula during use.
From the standpoint of packaging, it is preferable to be able to package the syringe and needle assembly with the attached hinged recap device in as small a package as possible. This helps reduce packaging costs while also reducing the amount of storage space required to store and/or transport the product. With hinged recap devices, particularly those in which the syringe and needle assembly are packaged with the hinged sleeve positioned to the side of the cannula, packaging costs can be of particular concern.
In light of at least the foregoing, a need exists for a safety needle assembly that is constructed to provide the desired protection against accidental needle sticks while also being constructed to facilitate usage by the user and to minimize packaging costs.
According to one aspect, a safety needle assembly includes a hub which includes a proximal end for connection to a syringe and a distal end, a cannula provided with a lumen and including a proximal end connected to the distal end of the hub and a beveled distal end, and a collar formed separately from the hub and mounted on the hub in rotationally fixed manner, with the collar including a sheath mounting portion. A protector is positioned over the cannula and covers the beveled distal end of the cannula, with the protector being removable to expose the cannula including the beveled distal end. A sheath includes an opening extending along at least a portion of the longitudinal extent of the sheath. The sheath is positioned outside the protector when the protector is positioned over the cannula and is pivotally connected to the sheath mounting portion of the collar to be pivoted, after removal of the protector to expose the cannula, towards the cannula so that the cannula passes through the opening in the sheath and is covered by the sheath.
Another aspect involves a safety needle assembly that includes a hub which includes a proximal end for connection to a syringe and a distal end, a cannula including a proximal end fixed to the distal end of the hub, with the cannula also including a lumen extending through the cannula and a distal end, a collar formed separately from the hub and mounted on the hub, with the collar including a pair of spaced apart mounting ears and with each of the mounting ears including two oppositely facing side surfaces. One of the side surfaces of one mounting ear faces one of the side surfaces of the other mounting ear, and each mounting ear has a width measured in a widthwise direction between distal and proximal ends of the mounting ear. One of the side surfaces of each mounting ear is provided with a first groove extending in the widthwise direction from a distal side of the mounting ear toward a proximal side of the mounting ear and the other side surface of each mounting ear is provided with a second groove extending in the widthwise direction from the proximal side of the mounting ear toward the distal side of the mounting ear, and each of the mounting ears is provided with a through hole formed by the overlapping first and second grooves. A protector is positioned over the cannula and covers the distal end of the cannula, with the protector being removable to expose the distal end of the cannula. A sheath is provided with an interior and an opening extending along at least a portion of a longitudinal extent of the sheath, with the sheath including a pair of pins each positioned in the through hole in one of the mounting ears to pivotally connect the sheath to the collar at a position outside the protector to permit the sheath, after removal of the protector to expose the distal end of the cannula, to pivot towards the cannula so that the cannula passes through the opening in the sheath and is positioned in the interior of the sheath in a position covered by the sheath.